I checked my To Do list this morning, and found that it wasn't going to record "Enterprise" tomorrow because the program was "no longer in the guide data." I checked, and sure enough, there's a seemingly "new" show scheduled for tomorrow night. I signed up for a season pass for "Star Trek: Enterprise."
Now, if your TiVo automatically records things you tend to like, it may grab this "new" show anyway, seeing as it has an awful lot of the same cast members as that show you "used" to watch on Wednesday nights. But don't take chances.